The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

This abandoned amusement park was built on a site with a dark history.

Abandoned blockhouses from Nazi Germany's Atlantic Wall erode into the sea on a French beach.

Giant topiary dog once played a role in a terrorist bomb plot.